Rotary drilling methods employing a drill bit and drill stems have long been used to drill wellbores in subterranean formations. Drilling fluids or muds are commonly circulated in the well during such drilling to cool and lubricate the drilling apparatus, lift drilling cuttings out of the wellbore, and counterbalance the subterranean formation pressure encountered. The recirculation of the drilling mud requires the fast and efficient removal of the drilling cuttings and other entrained solids from the drilling mud prior to reuse. Shaker separators are commonly used to remove the bulk solids from the drilling mud.
As is illustrated in FIG. 1 the current state of the art method for securing the shaker screen (2) to the shaker separator (not fully shown) involves the use of a wedge block retainer bracket (4) which is an integral part of the shaker separator and a wedge block (6). As one of skill in the art should know, the screen is placed in position underneath the wedge block retainer bracket and then the wedge block is pounded into position so as to secure the screen to the shaker separator. One of skill in the art should appreciate that the shaking motion of the shaking separator can cause the loosening of the wedge block if the wedged block is not fully secured. Given the current state of the art design, anecdotal accounts suggest that the operator often chooses to use a combination of a hammer and a suitable piece of wood in contact with the wedge block to deliver sufficient force to fully secure the wedge block. Unless care is used, premature physical damage to the screen and/or the wedge block may occur. It will also be appreciated by one of skill in the art that removal of a fully secured prior art wedge block is not a trivial operation.
Often removal of the wedge block involves the use of a pry bar engaged into the teeth (8) of the wedge block (6) and pivoted against a pivot point (not shown). Unless high levels of care are used, anecdotal accounts of this activity suggest that the potential for physically damaging the wedge block, physically damaging the screen, physically damaging the shaker and/or causing injury to the operating personnel is substantial. Thus there exists a continuing need for improved designs in the retention of the screen to the shaker and the wedge blocks that are used in such an operation.
A gasket is mounted to the shaker separator to seal the interface between the shaker screen and the support ledge of the shaker separator. The gasket sometimes is mounted to the support ledge using screws through the gasket into the support ledge. More often, the gaskets are mounted to the support ledge with through bolts. Because the gasket is subjected to abrasion and other damage as a result of being in direct contact with drilling fluids and solids, the gasket must be replaced from time to time. Removal of gaskets that are screwed or bolted to the support ledge often require grinding off the head of each fasteners used to mount the gasket to the support ledge as the heads are too worn to use common removal tools. This is considered “hot work” and can be undertaken only when the area is clear from explosive conditions, such as flammable liquids and fumes which could be ignited by sparks from the grinding process. It would be an improvement in the art to have a gasket mounted to a support ledge in such a way that the gasket may be removed without requiring “hot work” activities to be performed.